Contents

Prerequisites for Video Support

H.323 or SIP network for voice calls is operational.

Cisco Unified CME 4.0 or a later version.

Cisco Unified IP phones are registered in Cisco Unified CME.

Connection between Cisco Unified Video Advantage (CUVA) 1.02 or a later version and the Cisco Unified IP phone is up. From a PC with CUVA 1.02 or a later version installed, ensure that the line between the CUVA and the Cisco Unified IP phone is green. For more information, see Cisco Unified Video Advantage User Guide.

Correct video firmware is installed on the Cisco Unified IP phone.

– For Cisco Unified IP Phone 7940G and 7960G, 6.0(4) or a later version.

– Cisco Unified IP Phone 7970G, 7.0(3) or a later version.

– Cisco Unified IP Phone 7941G and7961G, 7.0(3) or a later version.

Note Other video-enabled endpoints registered with a Cisco Unified Communications Manager (Cisco Unified CM) can place video calls to Cisco Unified IP phones only if the phones are registered with a Cisco Unified CME and the appropriate video firmware is installed on the Cisco Unified IP phone.

If the Cisco Unified CM is configured for Media Termination Point (MTP) transcoding, a video call between Cisco Unified CME and Cisco Unified CM is not supported.

Video telephony is not supported with Cisco Unified CME MTP and codec g729/dspfarm-assist configuration under ephone.

If an SCCP endpoint calls an SCCP endpoint on the local Cisco Unified CME and one of the endpoints transferred across an H.323 network, a video-consult transfer between the Cisco Unified CME systems is not supported.

When a video-capable endpoint connects to an audio-only endpoint, the call falls back to audio-only. During audio-only calls, video messages are skipped.

For Cisco Unified CME, the video capabilities in the vendor configuration firmware is a global configuration. This means that, although video can be enabled per ephone, the video icon shows on all Cisco Unified IP phones supported by Cisco Unified CME.

Because of the extra CPU consumption on RTP-stream mixing, the number of video calls supported on Cisco Unified CME crossing an H.323 network is less than the maximum number of ephones supported.

Cisco Unified CME cannot differentiate audio-only streams and audio-in-video streams. You must configure the DSCP values of audio and video streams in the H.323 dial-peers.

If RSVP is enabled on the Cisco Unified CME, a video call is not supported.

A separate VoIP dial peer, configured for fast-connect procedures, is required to complete a video call from a remote H.323 network to a Cisco Unity Express system.

Video call is enabled on Cisco Unified CME, when the active call is held and resumed.

Information About Video Support

To configure video support for SCCP endpoints, you should understand the following concepts:

Video Support Overview

Video support allows you to pass a video stream, with a voice call, between two video-capable SCCP endpoints and between SCCP and H.323 endpoints. Through the Cisco Unified CME router, the video-capable endpoints can communicate with each other locally to a remote H.323 endpoint through a gateway or through an H.323 network.

Video capabilities are disabled by default, and enabling video capabilities on Cisco Unified CME does not automatically enable video on all ephones. You must first enable video globally for all video-capable SCCP phones associated with a Cisco Unified CME router and then enable video for each phone individually. Video parameters, like maximum bit rate, are set at a system level.

On Cisco Unified CME 8.6, calls made from SIP endpoints across a SIP trunk terminating on a non-CME endpoint (such as those controlled by a Cisco Unified CM or video conferencing MTU) require the following CLI to be configured to allow video:

voice service voip sip asymmetric payload full

The no supplementary-service sip moved-temporarily and no supplementary-service sip refer commands are not supported for video calls through a SIP trunk.

Supplementary services like call hold, call resume and call transfer are not supported on video calls between SCCP and SIP endpoints that are registered with CME. The call gets converted into audio-only mode when these supplementary services are invoked.

Matching Endpoint Capabilities

During phone registration, information about endpoint capabilities is stored in the Cisco Unified CME. These capabilities are used to match with other endpoints during call setup. Endpoints can update at any time; however, the router recognizes endpoint-capability changes only during call setup. If a video feature is added to a phone, the information about it is updated in the router’s internal data structure but that information does not become effective until the next call. If a video feature is removed, the router continues to see the video capability until the call is terminated but no video stream is exchanged between the two endpoints.

Note The endpoint-capability match is executed each time a new call is set up or an existing call is resumed.

Retrieving Video Codec Information

Voice gateways use dial-peer configurations to retrieve codec information for audio codecs. Video codec selection is done by the endpoints and is not controlled by the H.323 service-provider interface (SPI) through dial-peer or other configuration. The video-codec information is retrieved from the SCCP endpoint using a capabilities request during call setup.

Call Fallback to Audio-Only

When a video-capable endpoint connects to an audio-only endpoint, the call falls back to an audio-only connection. Also, for certain features such as conferencing, where video support is not available, the call falls back to audio-only.

Cisco Unified CME routers use a call-type flag to indicate whether the call is video-capable or audio-only. The call-type flag is set to video when the video capability is matched or set to audio-only when connecting to an audio-only TDM or an audio-only SIP endpoint.

Note During an audio-only connection, all video-related media messages are skipped.

Call Setup for Video Endpoints

The process for handling SCCP video endpoints is the same as that for handling SCCP audio endpoints. The video call must be part of the audio call. If the audio call setup fails, the video call fails.

During the call setup for video, media setup handling determines if a video-media-path is required. If so, the corresponding video-media-path setup actions are taken.

For an SCCP endpoint, video-media-path setup includes sending messages to the endpoints to open a multimedia path and start the multimedia transmission.

For an H.323 endpoint, video-media-path setup includes an exchange between the endpoints to open a logical channel for the video stream.

A call-type flag is set during call setup on the basis of the endpoint-capability match. After call setup, the call-type flag is used to determine whether an additional video media path is required. Call signaling is managed by the Cisco Unified CME router and the media stream is directly connected between the two video-enabled SCCP endpoints on the same router. Video-related commands and flow-control messages are forwarded to the other endpoint. Routers do not interpret these messages.

Call Setup Between Two Local SCCP Endpoints

For interoperation between two local SCCP endpoints on the same router, video call setup uses all existing audio-call-setup handling, except during media setup. During media setup, a message is sent to establish the video-media-path. If the endpoint responds, the video-media-path is established and a start-multimedia-transmission function is called.

Call Setup Between SCCP and H.323 Endpoints

Call setup between SCCP and H.323 endpoints is the same as it is between SCCP endpoints except that if video capability is selected, the event is posted to the H.323 call leg to send out a video open logical channel (OLC) and the gateway generates an OLC for the video channel. Because the router needs to both terminate and originate the media stream, video must be enabled on the router before call setup begins.

Call Setup Between Two SCCP Endpoints Across an H.323 Network

If call setup between SCCP endpoints occurs across an H.323 network, the setup is a combination of the processes listed in the previous two sections. The router controls the video media setup between the two endpoints and the event is posted to the H.323 call leg so that the gateway can generate an OLC.

Cisco Unified CME 8.6 and later versions add phone-based video support and Universal Serial Bus (USB) camera support for Cisco Unified IP Phones 8961, 9951, and 9971. The Cisco Unified IP Phones 8961, 9951, and 9971 display local video using the USB camera. Cisco Unified IP Phones 9951 and 9971 with phone load 9.1.1 decode remote incoming video RTP streams and display the video on the phone’s display screen. However, the video and USB camera capabilities of these two phones are disabled on Cisco Unified CME by default and are enabled by setting up the video and camera parameters in the phone provisioning file.

Cisco Unified CME 8.6 supports local SIP-video-to-SIP-video calls and SIP-video-to-SCCP-CUVA-video calls on Cisco Unified IP Phones 8961, 9951, and 9971 on the line side. On the trunk side, SIP video call is only supported with SIP trunk. H323 trunk is not supported for video calls on Cisco Unified IP Phones 9951 and 9971.

The media path for SIP video call is flow through and media flow-around is not supported for SIP line in Cisco Unified CME.

Video and Camera Configuration for Cisco Unified IP Phones

Cisco Unified CME uses the video and camera commands to allow video or camera to be enabled per phone, per template, or for global configuration. The video and camera commands are configured under the voice register pool, voice register template, and voice register global configuration modes. Once the commands are configured, the create profile command is required to have the phones provision file update with new configuration. For more information on enabling camera and video parameters on phones, see the “SIP: Enabling Video and Camera Support on Cisco Unified IP Phones 9951 and 9971” section.

The changes in video and camera configuration are applied to the phones when Cisco Unified CME sends the request to a phone through a service-control event in a SIP NOTIFY message. In earlier versions of Cisco Unified CME, SIP phones were required to reset and restart to update the new configuration parameters.

In Cisco Unified CME 8.6 and later versions, you use the apply-config command under voice register pool and voice register global configuration modes to dynamically apply the video and camera configuration changes to the phone configuration of Cisco Unified IP Phones 8961, 9951, and 9971 without restarting or resetting the phones and without causing any service interruption.

When Cisco Unified IP Phones 8961, 9971 and 9951 receive the apply-config request, the phones retrieve the new configuration file from the TFTP server and compare it with the existing configuration. The phones may restart themselves if there are any changes that requires a restart; otherwise, the phones apply the changes dynamically without restarting.

Bandwidth Control for SIP Video Calls

Video call bandwidth control is critical when there is a limit in resources. Typically, video calls require much higher bandwidth usage than audio-only calls. Video calls on Cisco Unified IP Phones 9951 and 9971 can use up to 1 Mbps for VGA quality video compared to 64 kbps plus overhead for a G711 audio call.

In Cisco Unified CME 8.6, the Cisco Unified SIP IP Phones 9951 and 9971 with VGA resolution offer 1-Mbps maximum bit-rate and answer with a lower value of received offer and 1 Mbps. Phones transmit video resolution and frame rate is set according to the maximum bandwidth bit-rate negotiated in the SIP offer or answer. Cisco Unified CME controls the SIP global bandwidth by configuring the bandwidth video tias-modifier bandwidth value [ negotiate end-to-end] command in voice register global configuration mode. The bandwidth control configuration is applied to the SIP phone dial-peer.

There are no new bandwidth changes in the SCCP CUVA side and the bandwidth configuration works the same as in earlier versions of Cisco Unified CME.

Flow of the RTP Video Stream

For video streams between two local SCCP endpoints, the Real-Time Transport Protocol (RTP) stream is in flow-around mode. For video streams between SCCP and H.323 endpoints or two SCCP endpoints on different Cisco Unified CME routers, the RTP stream is in flow-through mode.

Media flow-around mode enables RTP packets to stream directly between the endpoints of a VoIP call without the involvement of the gateway. By default, the gateway receives the incoming media, terminates the call, and then reoriginates it on the outbound call leg. In flow-around mode, only signaling data is passed to the gateway, improving scalability and performance.

With flow-through mode, the video media path is the same as for an audio call. Media packets flow through the gateway, thus hiding the networks from each other.

Use the show voip rtp connection command to display information about RTP named-event packets, such as caller-ID number, IP address, and port for both the local and remote endpoints, as shown in the following sample output:

Note Make sure you configure video command without configuring the camera command so that Cisco Unified IP phones 9951 and 9971 can switch from phone-based video camera to CUVA. If you configure both video and camera commands together, you may need to manually remove the USB camera from Cisco Unified IP phones 9951 and 9971.

Step 6

create profile

Router(config-register-global)# create profile

Generates provisioning files required for SIP phones and writes the file to the location specified with the tftp-path command.

The following example shows the video and camera commands configured under voice register pool 5. You can also configure both camera and video commands under voice register template configuration mode.

Apply-config is similar to resetting or restarting the phones and allowing the phones to update phone configuration files. Phones only reboot if needed. To apply video configuration to Cisco Unified IP phones 8961, 9951, and 9971, perform the following steps:

Prerequisites

Use the show ephone registered command to identify individual video-capable SCCP phones, by ephone-tag, that are registered in Cisco Unified CME. The following example shows that ephone 1 has video capabilities and ephone 2 is an audio-only phone:

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note The following table lists the Cisco Unified CME version that introduced support for a given feature. Unless noted otherwise, subsequent versions of Cisco Unified CME software also support that feature.

Table 39-1 Feature Information for Video Support

Feature Name

Cisco Unified CME
Version

Feature Information

SIP Trunk Video Support

7.1

Support was added for video calls between SCCP endpoints across different Cisco Unified CME routers connected through a SIP trunk.